The present invention relates generally to transmission systems and specifically to a gyroscopic, infinitely or continuously variable mechanical power transmission system.
Transmissions are widely employed on a wide variety of mechanized devices, including motor vehicles, construction machinery, excavation machinery, small electric motors, and the like. Manual and automatic transmissions, also known as speed changers or torque converters, typically employ gears, hydraulics, or friction to control transfer of torque from a power source to a load.
Conventional transmissions suffer from numerous problems. Transmissions generally have low mechanical and energy efficiencies, particularly when operating over the full range of output power requirements generally required in normal applications. Transmissions typically operate efficiently only at or near the output speeds corresponding to the input-to-output rotational speed ratios designed into the device. Additional mechanical and energy inefficiencies can result from the operational demands for starts, stops, and accelerations. Transmissions generally have slow response times, are bulky and/or heavy, are complex, and/or lack robustness.
Considerable resources have been expended towards developing a more energy efficient and operationally effective transmission system that overcomes these numerous problems. These efforts have been largely unsuccessful due to the need to make unacceptable compromises in cost, weight, and operational complexity to overcome mechanical and/or design limitations.
Objectives of the present invention include providing a transmission system that is continuously or infinitely variable, adaptable to wide ranges of use, is more mechanically and energy efficient, is inexpensive, has a fast response time, is small and/or lightweight, is capable of delivering maximum power on the one hand while operating efficiently and effectively through a wide range of power demands on the other, is robust and is operationally simple in design.
In a first embodiment, the transmission system includes:
(a) first and second input power shafts, the first input power shaft engaging the second input power shaft;
(b) a frame disposed to be rotated about a third shaft, the frame including a gyroscopic member, the gyroscopic member being rotated about an axis of rotation when torque is applied to the first input power shaft, the axis of rotation being transverse to a longitudinal axis of the third shaft; and
(c) a gear assembly rotatably disposed about an output power shaft. The gear assembly is engaged with the output power shaft, the second input power shaft, and the third shaft such that rotation of the gyroscopic member about the axis of rotation resists rotation of the frame by the gear assembly, thereby causing at least a portion of the torque applied to at least one of the first and second input power shafts to be transferred to the output power shaft.
The transmission system is particularly useful as an continuously or infinitely variable, mechanical power transmission, speed changer or torque converter. The system is capable of transmitting automatically a wide range of output torques by continuously or infinitely variable input-to-output speed ratios without the switching of gears or a torque converter; automatically delivering the output torques at the most appropriate input-to-output rotational speed ratio(s) relative to the output power needs, thereby ensuring power transmission at maximum efficiency and effectiveness; delivering output power torques over a wide range of output power requirements without the need for components such as bands, brakes, clutches, hydraulic torque converters, and special starters (which may require periodic adjustment, frequent maintenance, or replacement); transmitting extremely high horsepowers, achievable by high input-to-output speed ratios, with a transmission of nominal size and weight for the purpose of starting and moving extremely heavy vehicular loads such as heavy duty trucks, locomotives, and other types of heavy equipment; and achieving these results while maintaining a simple design, a light weight, a small cubature, a low cost of manufacture, and a robust construction.
The gyroscopic member can be any structure including one or more symmetrical disks, which are typically relatively heavy (e.g., 150 pounds or more), disposed concentrically about a central shaft (having the axis of rotation as its longitudinal axis) that is free to rotate about the axis of rotation which itself is confined within the frame. In other embodiments, the frame includes nested subframes that are free to rotate about one or more axes (i.e., have one or more degrees of freedom). The gyroscopic member has an axis of rotation that remains fixed with respect to space and will resist directional movement. The gyroscopic member can deliver a torque that is proportional to the angular velocity of the frame about an axis perpendicular to the gyroscope""s axis of rotation. Under the principle of conservation of angular momentum, the total angular momentum of any system of particles relative to any point fixed in space remains constant, provided no external force(s) act on the system.
In certain embodiments, the resistance of the frame (i.e., the gyroscope""s axis of rotation) to being rotated about the third shaft is attributable to the phenomenon of precession. This phenomenon is explained by Newton""s law of motion for rotation under which the time rate of change of angular momentum about any given axis is equal to the torque applied about the-given axis. Stated another way, the rate of rotation of the axis of rotation about a transversely oriented axis is proportional to the applied torque. This phenomenon is explained in detail below with reference to FIG. 1.
The gear assembly can include a number of interlocked gears and a number of parallel, rotatably mounted shafts to facilitate transmission of torque applied about the second input power shaft to the output power shaft.
In one specific configuration, the gear assembly includes a first gear at a proximal end of the gear assembly and a plate at a distal end of the gear assembly. The first gear and plate are rotatably mounted on different shafts (e.g., the second input power shaft and the output power shaft, respectively). The third shaft is attached to a second gear that engages the first gear. A fourth shaft and a fifth shaft are rotatably mounted on the first gear and plate.
A number of gears in the gear assembly are employed to more efficiently transmit torque from the input power shafts to the output power shaft. In an illustrative configuration, a third gear is attached to the second input power shaft, the third gear engages a fourth gear mounted on one of the fourth and fifth shafts, a fifth gear attached to the one of the fourth and fifth shafts engages a sixth gear on the other of the one of the fourth and fifth shafts, and a seventh gear attached to the other of the one of the fourth and fifth shafts engages an eighth gear mounted on the output power shaft.
The relative sizes of the gears in the gear assembly are important to the efficiency of the transmission. Preferably, the first gear is larger than the second gear, the third gear is smaller than the fourth gear, the fourth gear is smaller than a fifth gear, and the sixth gear is larger than the seventh gear.
To maximize resistance to rotation of the gear assembly by the gyroscopic member, the second gear is preferably significantly smaller than the first gear. Preferably, the gear ratio of the first gear to the second gear is at least about 2:1 and more preferably is at least about 3:1.
In another embodiment, the transmission system includes:
(a) a frame mounting a gyroscopic member, the gyroscopic member disposed to be rotated about an axis of rotation in response to rotation of an input power shaft, when torque is applied to the input power shaft; and
(c) a gear assembly rotatably engaged with an output power shaft and the input power shaft, such that the gear assembly is rotatable about the output power shaft in response to a power load on the output power shaft. Rotation of the gyroscopic member about the axis of rotation resists rotation of the gear assembly, thereby causing at least a portion of the torque applied to the input power shaft to be transferred to the output power shaft.
In yet another embodiment, a method of operation of a transmission system is provided. The method includes the steps of:
(a) applying torque to the input power shaft;
(b) rotating a gyroscopic member in response to the applying step, the gyroscopic member having an axis of rotation and being mounted on a frame member;
(c) rotating a gear assembly in response to the applying step, the gear assembly engaging the input power shaft and the output power shaft; and
(d) rotating the frame member and the axis of rotation of the gyroscopic member about a shaft engaging the gear assembly. Rotation of the axis of rotation resists rotation of the gear assembly. In this manner, at least a portion of the torque is applied to the output power shaft.
In one process configuration, the gyroscopic member is rotated by the engagement of a first gear attached to the input power shaft with a second gear attached to the gyroscopic member. In another process configuration, the gear assembly is rotated by the engagement of a third gear attached to the input power shaft with a fourth gear attached to a third shaft rotatably mounted on a fifth gear. In yet another process configuration, the frame member and axis of rotation are rotated by the engagement of a sixth gear attached to the shaft with the fifth gear.
In yet another process configuration, the gear assembly includes fourth and fifth shafts, which are parallel to one another and are mounted on common surfaces of the gear assembly. The fourth and fifth shafts are rotated to transmit torque applied to the input power shaft to the output power shaft.